TABLE 1.
Summary of individual effect sizes from original meta-analyses of the associations on tea consumption and risk of cancer included in the study
| Category | Number of effect sizes | Comparison details, % | n |
|---|---|---|---|
| Total | 154 | 100.0 | |
| By exposure (tea type) | |||
| Any tea | 78 | 50.7 | 38 Any vs. none 32 High vs. low 8 Increment of 1–3 cups/d |
| Black tea | 19 | 12.3 | 5 Any vs. none 11 High vs. low 3 Increment of 1–2 cups/d |
| Green tea | 57 | 37.0 | 12 Any vs. none 41 High vs. low 4 Increment of 1–2 cups/d |
| By study type | |||
| Case-control | 25 | 16.2 | |
| Cohort | 24 | 15.6 | |
| Observational (combined) | 105 | 68.2 | |
| By cancer type | |||
| Biliary tract cancer | 1 | 0.6 | |
| Bladder cancer | 7 | 4.5 | |
| Brain cancer | 3 | 1.9 | |
| Breast cancer | 31 | 20.1 | |
| Colorectal cancer | 8 | 5.2 | |
| Colon cancer | 1 | 0.6 | |
| Rectal cancer | 1 | 0.6 | |
| Endometrial cancer | 11 | 7.1 | |
| Esophageal cancer | 6 | 3.9 | |
| Gastric cancer | 17 | 11.0 | |
| Gallbladder cancer | 2 | 1.3 | |
| Glioma | 2 | 1.3 | |
| Renal cell carcinoma | 1 | 0.6 | |
| Liver cancer | 4 | 2.6 | |
| Lung cancer | 5 | 3.2 | |
| Leukemia (childhood) | 8 | 5.2 | |
| Leukemia (adult) | 2 | 1.3 | |
| Ovarian cancer | 12 | 7.8 | |
| Laryngeal cancer | 5 | 3.2 | |
| Oral cancer | 7 | 4.5 | |
| Oropharyngeal cancer | 3 | 1.9 | |
| Pharyngeal cancer | 3 | 1.9 | |
| Pancreatic cancer | 5 | 3.2 | |
| Prostate cancer | 7 | 4.5 | |
| Thyroid cancer | 1 | 0.6 | |
| Skin cancer (nonmelanoma) | 1 | 0.6 | |
| By level of evidence | |||
| Convincing | 2 | 1.3 | |
| Suggestive | 16 | 10.4 | |
| Weak | 25 | 16.2 | |
| Nonsignificant | 107 | 69.5 | |
| Not adequately assessed | 4 | 2.6 | |